Resinous materials of N-(isobutoxymethyl)acrylamide, styrene-butadiene or styrene-isoprene and an aldehyde are disclosed in U.S. Pat. Nos. 3,037,963 and 3,079,434 and can be utilized to form coating films having good flexibility, recoat adhesion and resistance to marring, staining, heat, detergents and corrosion. Neither patent discloses the coagulation of a polymer latex comprising these ingredients with metal salts nor any suggestion by which the green strength of synthetic rubber such as SBR could be improved.
U.S. Pat. No. 3,950,313 discloses polymer compositions having thermally reversible cross-links which can comprise an elastomeric interpolymer of vinylpyridine, styrene and butadiene, cross-linked with a metal from an organometallic compound which can be incorporated into the polymer by mixing. This patent, as the preceding two, is silent regarding the coagulation of a polymer latex with a metal salt and improving the green strength of SBR.
U.S. Pat. No. 3,808,168 discloses thermosetting coating compositions comprising resins which cure on baking via the condensation reaction of an N-methylol group, and ethers thereof, with volatile alcohols which resins are catalyzed to cure more rapidly or at lower temperatures by incorporating up to about 3% by weight, per weight of the resin, a dissolved inorganic metal salt wherein the metals include those in Groups I and II and the transition metals and the anions are halides, nitrates, phosphates, oxychlorides, fluoborates, fluosilicates or sulfates. The invention is illustrated with a methylolated acrylamide interpolymer in an organic solvent solution particularly one containing butanol and 2-butoxy ethanol and which forms an enamel paint with addition of a suitable pigment. There is no suggestion that the methylolated acrylamide interpolymer could be utilized to form a copolymer with styrene-butadiene and, in turn, cross-linked through certain metal ions to improve green strength.
Thus, coagulation of a polymer latex comprising an N-(alkoxymethyl)acrylamide and a diene or diene-containing synthetic rubber with metal ions has not been disclosed in the patents of which we are aware.